The value of the second plot point

The information delivered at the Second Plot Point changes the story (it has that quality in common with the First Plot Point) in such a way that the hero’s quest is accelerated. There are new doors opening, new strategies to be hatched, new risks with more immediate rewards.
At the Second Plot Point you can often smell the ending just around the bend.
You sense the story is turning that comer, that it is now a freight train that cannot be stopped. And yet, you’re not sure what it will hit, or precisely when.
At least, if you’re the reader. If you, the writer, aren’t sure yet, you’re in a deep pile of trouble at this point.
The Second Plot Point separates Part 3 from Part 4 at about 75 percent of the way through the story. Which means the hero transitions here from an attacking warrior to a hell-bent, selfless, heroic, and even martyr-like champion of all that is good. Or at least necessary in terms of solving the inherent dramatic problem at hand.
At the Second Plot Point the hero learns something that will take him one step closer, the final step, in fact, toward doing whatever needs to be done in Part 4 to bring the story to a satisfactory closure. Like the Midpoint, the Second Plot Point can deliver information that is not yet known or fully understood by the hero, but in such a case it still launches the final push toward the resolution. It’s the writer’s call — either the reader or hero, or both, need to know that the game has changed, and that at this point there are no more revelations ahead. What’s on the table is all there is to work with from this point forward.
In Dennis Lehane’s Shutter Island, the hero hooks up with a woman in a cave who appears to be the missing patient he’s been sent there to find. The hero has been through a lot and has concocted some theories of his own at this point, and this woman—who, it turns out, is completely imaginary within the hero’s delusional fantasy — sets him straight and, as a result, sends him out to save his partner from a lobotomy at die hands of the evil doctor, all of it going down at the dark and scary lighthouse we’ve seen glimpses of before.
The chase is on, the fuse is lit. The hero now knows everything, and won’t be stopped in his quest to make things right. Classic Second Plot Point stuff.
This is the last piece of new information in the story. From this point on, Langdon has everything he needs (or at least, everything he’s going to get) to uncover the truth and ultimately deduce the location of the Holy Grail itself.
This pivotal shift is the Second Plot Point, and it occurs right where it is supposed to be found in a solid story.